1. Field of the Invention
The invention relates to a subgroup B recombinant human adenovirus vectors Ad11-5EP and Ad11-5ETel-GFP and methods for constructing and for using the same.
2. Description of the Related Art
Adenovirus 11 (Ad11) is a serotype of the subgroup B human adenovirus and is obviously superior to Ad 5 in oncolytic virotherapy. Ad11 is able to combine other cell surface receptor X besides the CD46 receptor. Tuve has reported that Ad11 is the only virus in the B subgroup adenovirus that is able to combine CD46 as well as the surface receptor X, which indicated that Ad11 is capable of infecting a much wider spectrum of tumor cells, thereby solving the problem of low infection rate in the application of Ad5 due to downregulation of virus acceptor. Ad11 is also superior to Ad5 in that the content of neutralizing antibodies of Ad11 is relatively low, being 10-31%, compared with 45-90% of that of Ad5, and the neutralizing antibodies of Ad11 have no cross-reactivity. When Ad11 is intravenously injected to transgenic mice expressing CD46, no obvious intrahepatic transduction or hepatotoxicity occurs. Furthermore, Ad11 is able to effectively transduce dendritic cells, allows tumor-specific antigens to express, and enhances the immune response to benefit the cancer therapy.
Studies on other adenovirus serotypes except Ad5 used as a vaccine or gene conversion vector have been reported, but the use of the adenovirus serotype used as an oncolytic virus has been rarely conducted. In vitro and in vivo studies from Sandberg indicated that transduction, replication, and lysis of Ad11 effectively undergo in prostate cancer cell line PC-3, but the comparison between Ad5 was not conducted by Sandberg. Shashakova et al. have compared oncolytic efficacy among Ad5, Ad6, Ad11, and Ad35 based on in vitro studies on human tumor cell lines and in vivo studies on human prostate cancer cell lines DC 145, and found that Ad5, Ad6, and Ad11 have similar antitumoral efficacy whereas Ad35 has no antitumoral efficacy. The most important is that only Ad5 has hepatotoxicity. After that, chimeric oncolytic Ad5 (by substituting cilium of Ad5 by that of the B subgroup adenovirus) was constructed for allowing the chimeric oncolytic Ad5 to combine with membrane receptor CD46 to improve the antitumoral efficacy. However, compared with a whole B subgroup adenovirus, this method is not able to overcome the neutralizing ability of hexon antigen of Ad5.
The number of circulating tumor cells (CTCs) is in relation to the clinical stage, treatment effect, and short survival rate. CTCs level in peripheral blood in tumor patient is taken as the basis for monitoring, adjusting the treatment, and anticipating the results. Thus, a specific and sensitive method for detecting these cells is necessitated. In recent years, immune cells counting analysis and quantitative PCR have been applied by which a small amount of CTCs were detected, however, the application of these methods were restricted because of a high testing cost and the lack of specific biological markers.
Replication-selective oncolytic adenovirus is a new kind of medicine for treating tumors. To be noted, it has been reported recently that the replication-selective oncolytic adenovirus expressing GFP has been used to detect CTCs among more than hundred million of peripheral blood cells. However, genetic variation of tumor cells is a very important factor affecting the infection ability of adenovirus. A low expression of CAR in tumor cells significantly decreases the infection ability of Ad5, which further influences the positive rate of tumor cells. Besides the known influence mechanism of the low expression of CAR, it has also been found that other tumor related genes like CEACAM6 influences Ad5 from entering the nuclear, thereby decreasing the infection ability of Ad5 on tumor cells. These data indicate that methods for testing CTCs using Ad5 have a low sensitivity in some tumor cells.